Airlines are charging a hidden fee that's increasing your plane ticket — and they won't say what it's for

Shutterstock/Ekaterina Pokrovsky Few spend time analyzing the breakdown of a plane ticket.

Our modus operandi is to compare ticket prices, usually through a website like Expedia or Kayak, pick whichever deal we can manage to glean, and jet away.

But those willing to take a closer look will see that, for international flights, there is a fee tacked on that inflates the end cost by a few hundred dollars. Often labeled as a "carrier fee" or "carrier-imposed fee," there is no clarity as to what the fees are for and how high they can be.

The ticket breakdown of a Delta international flight. Screenshot Some have argued that these fees are a sly way for airlines to keep a fuel surcharge, despite the price of oil dropping.

In a 2012 Department of Transportation ruling, airlines were told that the fuel surcharge must "reflect a reasonable estimate of the per-passenger fuel costs incurred by the carrier."

As such, fuel surcharges have pretty much disappeared from the ticket breakdown, but that doesn't mean they actually went away. Many argue that the surcharge was wrapped into the carrier fee, which is why the fee can be as high as $650 for a one-way flight, as is the case with Delta.

"The reality is that enough carriers are maintaining the fuel surcharges," Greg Geronemus, co-CEO of tour-package provider smarTours, told Business Insider. "It's their unspoken understanding of, 'let's enjoy this while it lasts and keep the fuel surcharge high.'"

Airlines aren't jumping at the opportunity to clarify what these carrier fees are for, either.

"In terms of what it covers, it's a wide-ranging fee. You're allowed to use it to collect money for a lot of different things," Josh Freed, a spokesperson for American Airlines, told Business Insider.

Freed declined to comment on what in particular could fall into that fee, only stating that "almost every expense the airline has can be covered by that fee." A Delta spokesperson also declined to comment on what the fees pay for, only adding, "Delta only has a fuel surcharge where it's required by the government."

The Department of Transportation deferred comment on carrier fees to the Federal Aviation Administration. The FAA did not respond to multiple requests for comment on whether regulatory oversight existed dictating what carrier fees are used for and how high they can be.

The ticket breakdown of a Cathay Pacific international flight. Screenshot

So how does it affect your bottom line? That's also a bit unclear. Delta writes on its website that "carrier-imposed surcharges" can amount to as much as $650 for a one-way international flight. Freed of American Airlines said there's no rule that dictates what the fee can amount to.

A one-way, $1,498 Delta ticket from New York to London listed a $259 carrier-imposed international surcharge. A randomly selected, one-way $1,977 American Airlines flight from New York to London also imposed a $259 carrier-imposed fee.

That doesn't mean you're always shelling out an extra $200 for an international ticket. A randomly selected United Airlines ticket totaling $1,498 for a one-way ticket from New York to London didn't list a carrier fee at all.

Geronemus also made a point of noting that Cathay Pacific, the flag carrier for Hong Kong, eliminated its fuel surcharge through the carrier fee. A randomly selected flight from New York to Hong Kong amounted to roughly $544, and it explicitly lists that there is no carrier fee.

So it should it matter that carrier fees exist with no insight as to what they are used for and how high they can be? Freed claims it shouldn't.

"What goes into that [fee] for customers doesn't really matter because the competition happens at the cost-of-the-ticket level," Freed added. "It's really a non-issue for customers because there's various competition on what a ticket costs to go anywhere."